Simulation of Plume Evolution after Shallow Gas Well Blowout in Deepwater Open-Circuit Drilling
In the process of deep-water open-circuit drilling,it is easy to encounter shallow gas formations.The shallow gas layer has a high-pressure nature,which can easily lead to well surge or even blowout,threatening the drilling safety.In this study,based on the CFD-PBM(population balance model)simulation method,a plume motion model including fluid transport and hydrate phase change is established to study the formation and evolution of the plume after a shallow gas blowout occurs during deepwater open-circuit drilling.The results show that hydrate generation exists at the early stage of fluid intrusion into the wellbore,and the amount of generation is higher near the well wall.When the wellbore fluid is spewed out,the main body of natural gas is transported with a lag,and the hydrate stream will be spewed out of the wellbore with the gas front first,after which the main body of gas is spewed out.In the early stage of well blowout,the fluid will go through the process of straight jet flow,jet branching,jet bending,and diffusion to form a plume,and at the same time,in the seawater depth that meets the conditions for hydrate generation,the hydrate is continuously transported by the gas plume.This study summarizes the transport and evolution of the gas bubble plume after the blowout of deepwater open-circuit drilling wells,which can provide a favorable basis and reference for the safety measures after the deepwater blowout.
DeepwaterOpen-circuit drilling(Riserless drilling)Shallow gas well blowoutPlumeHydrate
万方数据
维普
